During tumor progression, NK cells can also be educated by tumor cells, which can switch anti-tumor immunity to pro-tumor immunity, creating an immune-tolerant microenvironment that facilitates tumor cell growth or metastasis.161 For example, murine NK cells isolated from the spleen of mice bearing keratin-14+ breast cancer cells show increased expression of inhibitory receptors such as LAG3, LKRG1, and KLRC1. Here, KLRC1 is linked to neoplasm.